SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15c34c410c01ed45e7138f9cb10222e7d7fda98d0e7efacc8d7003cd78ae0810' 
  AND token = 'WkRPE/SHk11jBeksnakEw7XXfx1mX3hxq0Ysf6RfMvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables